Calipers



H. KOEBKE.

CALIPERS.

APPLICATION FILED SEPT. Il I`921.

Patented Aug. 22, 1922.

Henrg Kn @Eke @u ww aan M HENRY KOEBKE,OF WAUKESHAg WISCONSIN.

GALIPERS.

To all whom t may concern.'

Be it known that I, HENRY Konxn, a citizen ofthe United States, and resident of "Waukesha, in the county of Waukesha and State of llisconsin, have invented certain new and useful improvements in Calipers; and l do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to a new and useful improvement in calipers, and is more particularly adapted for instruments of this kind which are used for taking inside measurements.

One of the principal objects of the invention is to provide an improved structure for mounting the arms which are projected into the interior of the article, the diameter of which is to be measured.

A further object of the invention is to provide, in connection with measuring arms, an improved means for locking them in their projected position until the distance between the points thereof can be measured.

lilith the above and other objects in view, the invention consists in certain structural details which will be described in connection with the accompanying drawing in which,

Figure 1 is a sectional plan view of the `device taken on the line 1 1 of Figure 2, and

Figure 2'is a cross sectional view on the line 2 2 of Figure 1.

The instrument which comprises my invention comprises a housing which is composed of a pair of complementary sections 5 and G which are secured together by the fastening elements 7. A pair of arcuate bores 8 and 9 is formed in the housing where the two sections thereof join. rlhese'bores` are therefore located in a common plane with the convex faces thereof approaching each other, as shown, and avpair of plungers 10 is reciprocably mounted therein.

An expansile spring 11 is located in the bottom of each bore and acts between the bottom thereof and a seat in the inner end of the plunger. A channel 12 is formed in the wall of each bore, and extends longitudinally throughout a portion of the length thereof. A pin 13 is secured to the plunger near its inner end and rides in this channel,

Specification of Letters Patent.

)Patented Aug. 22, 1922.

Application filed September 1, 1921. Serial No'. 497,489.

and a shoulder 141 is adapted to engage the pin to limit the extent of the outward projection of the plunger. The housing is also cut away, as shown, at 15, to provide a space which extends between the two bores and is adapted to receive a wedge 1G. This wedge is swiveled on the end of a rod 17 which extends through a handle 18 and has a threaded engagement therewith. The end of the rod 17 is provided with a knurled knob 19 by means of which it may be advanced to engage and lock the plungers 10, or may be retracted to release the same.

In using my device, the plungers 10 may first be pushed back into the bores and locked therein, by advancing the wedge 16. The end of the instrument is then inserted into the article which is to be measured and the plungers are released. Under the influence of the springs 11, the plungers will be projected to engage the highest points of the interior of the recess to be measured, whereupon the Wedge 16 may be adjusted to lock the same in this position until the same can be measured.

l claim as my invention:

1. A device of the character described comprising an elongated housing having therein a pair of bores curved toward each other, plungers reciprocable in said bores, springs seated in the bottoms of bores and urging the plungers outwardly and means for locking the plungers against movement.

2. A device of the character described comprising an elongated housing having therein a pair of bores curved toward each other, plungers reciprocable in said bores, a channel in the wall of each of the bores and extending longitudinally throughout a portion of its length, a pin secured to the plunger and riding in the channel, and engageable with the end of the channel to limit the movement of the plunger, springs seated in the bottoms of the bores and urging the plungers outwardly, and means for locking the plungers against movement.

3. A. device of the character described comprising an elongated housing having therein a pair of arcuate bores disposed with their convex Sides approaching each other, plungers reciprocable in said bores, a channel in the wall of each'of the bores and extending longitudinally throughout a portion of its length, a pin secured to the plungers and 'riding 1n the channel and engageeble n With the end of the .channel tov limit the movement of the plunger, springs seated in the bottoms of the bores and urging the plungers outwardly, said housing having a space therein extending between the bores and a Wedge adjustable therein to engage HENRY KOEBKE. 

